Quickly power amplifier control (Quickly Power Amplifier Control, referred to as QPC), as the latest energy-saving technology for a mobile terminal, may immediately enable an uplink power amplifier (Power Amplifier, referred to as PA) to perform final power amplification on a signal to be sent to a base station when a mobile terminal has data to be sent, and promptly disable the uplink PA after the mobile terminal sends data to the base station, thereby reducing power consumption of the uplink PA.
With the QPC in the prior art, to maintain constant transmit power of an existing terminal, an uplink power amplification link for the terminal adopts the scheme that one stage of variable gain amplifier and one stage of fixed gain amplifier are cascaded. Automatic gain control (Automatic Gain Control, referred to as AGC) is used to control the variable gain amplifier and the fixed gain amplifier, and meanwhile closed-loop power control is used to ensure the stable output power of the terminal, that is, a base station controls, according to the received transmit power of the terminal, the transmit power of the terminal by using an air interface message.
In the prior art, after data is transmitted from the terminal to the base station, the uplink PA is directly disabled. An automatic gain controller does not learn that the uplink PA is disabled, and during the period of time when the uplink PA is disabled, continues to increase the transmit power until adjusting the power to a maximum value. When the uplink PA is enabled again, the uplink PA is enabled with gull gain and transmits a signal. As a result, the transmit power of the mobile terminal when the PA is enabled is different from the transmit power of the mobile terminal when the PA is disabled.